Service names and port numbers are used to distinguish between different
services that run over transport protocols such as TCP, UDP, DCCP, and
SCTP.
Service names are assigned on a first-come, first-served process, as
documented in [RFC6335].
Port numbers are assigned in various ways, based on three ranges: System
Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private
Ports (49152-65535); the difference uses of these ranges is described in
[RFC6335]. According to Section 8.1.2 of [RFC6335], System Ports are
assigned by the "IETF Review" or "IESG Approval" procedures described in
[RFC8126]. User Ports are assigned by IANA using the "IETF Review" process,
the "IESG Approval" process, or the "Expert Review" process, as per
[RFC6335]. Dynamic Ports are not assigned.
The registration procedures for service names and port numbers are
described in [RFC6335].
Assigned ports both System and User ports SHOULD NOT be used without
or prior to IANA registration.
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* PLEASE NOTE THE FOLLOWING: *
* *
* ASSIGNMENT OF A PORT NUMBER DOES NOT IN ANY WAY IMPLY AN *
* ENDORSEMENT OF AN APPLICATION OR PRODUCT, AND THE FACT THAT NETWORK *
* TRAFFIC IS FLOWING TO OR FROM A REGISTERED PORT DOES NOT MEAN THAT *
* IT IS "GOOD" TRAFFIC, NOR THAT IT NECESSARILY CORRESPONDS TO THE *
* ASSIGNED SERVICE. FIREWALL AND SYSTEM ADMINISTRATORS SHOULD *
* CHOOSE HOW TO CONFIGURE THEIR SYSTEMS BASED ON THEIR KNOWLEDGE OF *
* THE TRAFFIC IN QUESTION, NOT WHETHER THERE IS A PORT NUMBER *
* REGISTERED OR NOT. *
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